Suggest Alternate Medications For Arimidex And Fremara

I have had some severe reactions to the pill Arimidex and I am now on Fremara. Between both pills I have gained about 20lbs in the past 8 months. I m on a very good appropriate eating program. During the time I was on Arimidex my bones and muscles and the headaches were seeming to be killers for me. Are these deal breakers for me to not take these pills and are there other pills I can take? My lower back is another condition since taking the pills. Help!!!